#include "qtlogbrowser.h"

#include <QPainter>
#include <QTextBlock>


QtLogBrowser::QtLogBrowser(QWidget *parent) : QPlainTextEdit(parent)
{
    this->setReadOnly(true);
    this->setUndoRedoEnabled(false);
    this->setFont(QFont("Consolas", 11));

    lineNumberArea = new LineNumberArea(this);
    highLighter = new LogHighLighter(this->document());

    connect(this, &QtLogBrowser::blockCountChanged, this, &QtLogBrowser::updateLineNumberAreaWidth);
    connect(this, &QtLogBrowser::updateRequest, this, &QtLogBrowser::updateLineNumberArea);
#if 0
    connect(this, &QtLogBrowser::cursorPositionChanged, this, &QtLogBrowser::highlightCurrentLine);
    highlightCurrentLine();
#endif


    updateLineNumberAreaWidth(0);
}


int QtLogBrowser::lineNumberAreaWidth()
{
    int digits = 1;
    int max = qMax(1, blockCount());
    while (max >= 10) {
        max /= 10;
        ++digits;
    }

    int space = 10 + fontMetrics().horizontalAdvance(QLatin1Char('9')) * digits;

    return space;
}


void QtLogBrowser::updateLineNumberAreaWidth(int /* newBlockCount */)
{
    setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
}

void QtLogBrowser::updateLineNumberArea(const QRect &rect, int dy)
{
    if (dy)
        lineNumberArea->scroll(0, dy);
    else
        lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());

    if (rect.contains(viewport()->rect()))
        updateLineNumberAreaWidth(0);
}

void QtLogBrowser::resizeEvent(QResizeEvent *e)
{
    QPlainTextEdit::resizeEvent(e);

    QRect cr = contentsRect();
    lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
}


void QtLogBrowser::highlightCurrentLine()
{
    QList<QTextEdit::ExtraSelection> extraSelections;

    if (!isReadOnly()) {
        QTextEdit::ExtraSelection selection;

        QColor lineColor = QColor(Qt::yellow).lighter(160);

        selection.format.setBackground(lineColor);
        selection.format.setProperty(QTextFormat::FullWidthSelection, true);
        selection.cursor = textCursor();
        selection.cursor.clearSelection();
        extraSelections.append(selection);
    }

    setExtraSelections(extraSelections);
}


void QtLogBrowser::lineNumberAreaPaintEvent(QPaintEvent *event)
{
    QPainter painter(lineNumberArea);
    painter.fillRect(event->rect(), this->palette().base().color());

    QTextBlock block = firstVisibleBlock();
    int blockNumber = block.blockNumber();
    int top = qRound(blockBoundingGeometry(block).translated(contentOffset()).top());
    int bottom = top + qRound(blockBoundingRect(block).height());

    while (block.isValid() && top <= event->rect().bottom()) {
        if (block.isVisible() && bottom >= event->rect().top()) {
            QString number = QString::number(blockNumber + 1);
            painter.setPen(this->palette().text().color());
            painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(), Qt::AlignRight, number);
        }

        block = block.next();
        top = bottom;
        bottom = top + qRound(blockBoundingRect(block).height());
        ++blockNumber;
    }
}


LogHighLighter::LogHighLighter(QTextDocument *parent) : QSyntaxHighlighter(parent)
{
    HighlightingRule rule;

    /* timestamp */
    QTextCharFormat objectFormat;
    objectFormat.setForeground(QColor("#008897"));
    rule.pattern = QRegularExpression(QStringLiteral("(\\[[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}\\])"));
    rule.format = objectFormat;
    highlightingRules.append(rule);

    QTextCharFormat errorFormat;
    errorFormat.setFontWeight(QFont::Bold);
    errorFormat.setForeground(QColor("#ff465e"));
    rule.pattern = QRegularExpression(QStringLiteral("(\\[ERROR\\])"));
    rule.format = errorFormat;
    highlightingRules.append(rule);

    QTextCharFormat infoFormat;
    infoFormat.setForeground(QColor("#84bb4c"));
    rule.pattern = QRegularExpression(QStringLiteral("(\\[INFO\\])"));
    rule.format = infoFormat;
    highlightingRules.append(rule);
}

void LogHighLighter::highlightBlock(const QString &text)
{
    for (const HighlightingRule &rule : qAsConst(highlightingRules)) {
        QRegularExpressionMatchIterator matchIterator = rule.pattern.globalMatch(text);
        while (matchIterator.hasNext()) {
            QRegularExpressionMatch match = matchIterator.next();
            setFormat(match.capturedStart(), match.capturedLength(), rule.format);
        }
    }
}


